<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
  <title> New Document </title>
  <meta http-equiv="Content-type" content="text/html;charset=utf-8"  >
  <meta name="Generator" content="EditPlus">
  <meta name="Author" content="">
  <meta name="Keywords" content="">
  <meta name="Description" content="">
<script type="text/javascript">
	window.onload() = init;
	function init(){		
		var btn = document.getElementById("btn")
		btn.onclick = function(event){
			//判断赋值
			event = event||event.type;
			document.write(event+"<br/>");
			document.write(event.type+"<br/>");
			document.write(this.value+"<br/>");
		}
	}
	
</script>
</head>

	<body>
		<ul>
			<li>aaaaaa</li>
			<li>bbbbbb</li>
			<li>cccccc</li>
			<li>dddddd</li>
		</ul>
		<input type="button" value="点击" id="btn">
		<script type="text/javascript">

		</script>
		
		
	</body>
</html>
